Function Reference

IsDeclared

Check if a variable has been declared.

IsDeclared ( expression )

Parameters

expression string representing name of the variable to be checked.

Return Value

Success: Returns 1 for Global variable or variable declared outside functions.
Special: -1 for Local variable.
Failure: Return 0 when no variable can be found.

Remarks

If there is a need to use IsDeclared() to check that a variable exists, then in most situations Assign() should be used to create/write to the variable and Eval() should be used to read from the variable.

Related

Assign, Eval

Example


If Not IsDeclared("a") Then
    MsgBox(0, "", "$a is NOT declared") ; $a has never been assigned
EndIf

Local $a = 1

If IsDeclared("a") Then
    MsgBox(0, "", "$a IS declared") ; due to previous $a=1 assignment
EndIf